1. Technical Field
The present invention relates to a method of designing a welding method, a welding method, a welded joint body and the like. More particularly, the present invention relates to a method of designing a welding method in which a metal glass and a crystalline metal satisfying given conditions are selected and thus a welded joint body having a sufficient strength is obtained, a welding method, a welded joint body and the like, and also relates to a welded joint body in which a metal glass and a crystalline metal are joined by welding and a joint body having a sufficient strength is obtained and the like.
2. Description of the Related Art
A metal glass that is formed with a nanocrystalline metal or an amorphous metal has excellent properties in strength and hardness, abrasion resistance, corrosion resistance and the like; it is expected that the metal glass will be utilized in many fields.
However, although the metal glass has such excellent properties, it disadvantageously has difficulties in processing and weldability. While, in order for the fields of its applications to be extended, a welding joining technology between metal glasses is important, in order to produce actual device components and the like, it is necessary to have a technology for joining a metal glass and a crystalline metal (actually used metal material) having a crystalline structure. As joining means for realizing the joining technology, examples in which an explosion bonding method, a friction pressure welding method and a welding method are applied have been reported.
However, when, as the joining means, a welding method of melding a joined portion is applied, a metal glass and a crystalline metal melt together in a molten portion formed on a butt surface to reduce a glass formation ability and thus form a brittle intermetallic compound, with the result that a joint body having a sufficient weld strength often fails to be obtained.
Hence, Materials Transactions, Vol. 42. No. 12 (2001), p. 2649-2651 discloses as an example that, since welding using, as a welding heating source, a high energy beam such as an electron beam or a laser beam that can form a sharp melting shape and that is suitable for local rapid heating and rapid cooling reduces the melting of both joint members in the welded portion and achieves the rapid heating and the rapid cooling, a welding method of applying the high energy beam to the butt surface between the metal glass and the crystalline metal is applied.